In a strict chemical sense an “organic pesticide” is one which is an organic chemical as that term is understood in chemistry. But in the present context an “organic pesticide” is one that is environmentally friendly. By this definition, few pesticides are organic. The term “natural” is also used to describe such materials and compositions.
It may be preferred to use a “natural” or “organic” pesticide when controlling pests.
Organic pesticides are usually considered as those pesticides that come from natural sources. These natural sources are usually plants, as is the case with pyrethrum (pyrethrins), rotenone or ryania (botanical insecticides), or minerals, such as boric acid, cryolite, or diatomaceous earth. Organic pesticides are largely insecticides.
Even if a product is considered to be organic, it is still a pesticide. It is important to be careful when using any pesticide, even organic or natural pesticides. Just because a product is thought to be organic, or natural, does not mean that it is not toxic. Some organic pesticides are as toxic, or even more toxic, than many synthetic chemical pesticides. Organic pesticides have specific modes of action, just as do synthetic pesticides.
To determine the relative toxicity of any pesticide to humans, check the signal word given on the pesticide label. Least toxic products carry the signal word CAUTION on their label. Products with the signal word WARNING on the label are more toxic. The most toxic pesticides have the signal word DANGER on their labels. Signal words are not an indication of the potential for environmental harm.
While some organic pesticides may be nontoxic or are only slightly toxic to people, they may be very toxic to other animals. For instance, the organic pesticide ryania is very toxic to fish. Also, some organic pesticides may be toxic to beneficial insects, such as honeybees, if they are combined with other materials, such as combining pyrethrins with rotenone.
Nature has given us plant extracts that make very effective pesticides and insect repellents. For example, some organic pest control products such as Orange Guard use a citrus-fruit peel base, such as from lemons and oranges. Citrus oils kill many flying and crawling insects on contact by destroying the waxy coating of the insect's respiratory system.
Other organic pesticides use natural extracts to repel rather than kill pests. Some products use garlic or hot peppers and essential oils of herbs such as cloves to repel insects and other pests.
The “natural” and “organic” pesticides kill with a chemical action.